Apparatus for the control of gunfire on shipboard



Sept, 23, 1924. ma ma A. BARF! ET AL APPARATUS FOR THE CONTROL OF GUNFIRE ON SHIPBOARD Filed Sept. 1, 1922 3 Sheets-Sheet 1 F75 Ll.

Sept 23, mm. 11,509,333

IA. BARR ET AL APPARATUS FOR THE CONTROL OF GUNFIEE ON SHIPBOARD Filed Sent. 1,, 1922 3 Sheets-Sheet. 2

fiapta 23. 1924. a sowzs A. BARR ET AL APPARATUS FOR THE CONTROL CF GUNFIRE ON SHIPBOARD Filed Sept. 1, 1 3 Sheets-Sheet 5 W V W $0M m4 Wary I atented Sept. 23, 1924;.

UNETEE STATES PATENT OFFICE.

AROHIBALD BARR AND WILLIAM STROUD, 0F ANNIESLAND, GLASGOW, SCOTLAND,

ASSIGINORS TO BARR AND STROUD, LIMITED, OF ANNIESLAND, GLASGOW, SCOT- LAND.

APPARATUS FOR THE CONTROL OF GUNFIRE 0N SHIPBOARD.

Application filed September To all whom it may com-era:

Be it known that we, ARC-HIBALD BARR and l VILLIAM STRoUn, subjects of the Kin of Great Britain and Ireland, and both of axton Street, Anniesland, Glasgow, Scotland, have invented new and useful Improvements in Apparatus for the Control of Gunfire on Shipboard, of which the following is a specification.

This invention relates to means for use in determining the correct setting of a gun mounted upon a latform subject to pitching or rolling or pitching and rolling such as a battleship at sea so that it may be fired at any part of the pitch or roll, and the motion which may be either roll or pitch or a resultant of these and with which the invention principally deals will hereinafter be referred to as rock.

Under conditions when the target is-right ahead in the prolongation of the fore andaft line of a ship which is rolling but not pitching and assuming that the target and ship are stationary in position and that the gun is elevated to the angle appropriate for the range, the target should be hit if when the gun is fired the angle of roll is zero but if tired when at any other point of the roll a considerable error mainly in azimuth would arise and the object of this invention is to provide apparatus to which motion in conformity with the rock as the rock occurs is transmitted whichacting in conjunction with additional mechanism operates to determine the correction required to be applied to the gun in order that it may be fired at each and every point of the rock.

In the following description it will generally be assumed that the deflection due to the relative motion of the ship and the target is zero, except when specially referred to.

In the general case the errors to be dealt with are a function of four independent variables, viz (1) or, the angle between the bearing of the target and the, fore and aft line, (2) 9, the elevation of the gun corresponding to the known range, (8) the angle of roll, and the angle of pitch.

We can, however, at once simplify the problem very materially by considering separately (a) the effect of an angular dis placement of the platform upon which the gun is mounted about the line of sight to the target, and (b) the efiect of an angular motion in the vertical plane containing the line of sight. Cause (a) will affect the azimuthal correction and only to a very slight extent the correction for gun elevation p. Cause (6) will not effect the azimuthal correction.

In order to effect the separation referred 0 to, we may place at some convenient station on the battleship, say in the fire control room, two motion following mechanisms one for following the rock, the other for following the angular motion perpendicular to the plane of rock. These mechanisms may be mounted together or separately upon aplatform or platforms which are rotated about an axis (or axes) perpendicular to the deck or nearly so, in accordance with the change in bearing (or line of sight) of the target. One of these, the follow the rock mechanism, has its horizontal axis (about which it can turn) parallel to the line of sight, while the second has its corresponding horizontal axis perpendicular to the line of sight. As the bearing of the target alters, its value is to be transmitted to the mechanisms so that their axes are constantly maintained azimuthally parallel and perpendicular respectively to so the line of sight. The second mechanism having its axis perpendicular to the line of sight will, however, not be required if the gun sight is directed on the target in elevation, nor will it be required if director 8 firing is employed. We may accordingly use one follow the rock mechanism only in such cases. In fact the second motion following mechanism would only be required for pure indirect fire.

The follow the rock mechanism may take the following form A Mallock (or other) roll indicator may be used, so mounted that its case supporting its stabilized drum can be rotated by suitable gearing so that a pointer on its dial al ways records the same reading, viz zero roll; then the motion of the said gearing can be employed to impart to any apparatus a motion proportional to the roll. Instead of rotating the case of the roll indicator, we may rotate a pointer so as to kee 3 it in alignment with a mark on the drum of the roll indicator, for example, by hand control.

So far as the correction of bearing is concerned, we now have a comparatively simple problem to solve: This correction, instead of being a function of four independent variables is now a function of two. only, viz (1) the reel: ,0 and (2) the angle of elevation of the gun corresponding to the known range, and in accordance with this invention motions according to rock 9 and angle of ele vation c of the gun may be comn'iunicated at any point of the rock to calculating mechanism which operates to give the correction required. For example, a surface cam of any suitable type may be used having two degrees of freedom, one degree of freedom being for settings corresponding to the value of the rock which may be imparted to the cam by the gearing which has restored the index of the roll indicator to zero the sea ond degree of treedom for settings corresponding to the range, or the corresponding gun elevation o.

In place of a Mallock roll indicator a long period pendulum or a gyro spinning about a vertical axis may be used, and the apparent motion of the gyro (or other roll indica tor) be communicated to the surface cam.

When the ship or target, or ship and target are not stationary in position, the correction in bearing obtained after the manner described is to be added on algebraically (say by means of a differential gear) to the hearing which in the absence of rock would be communicated to the guns.

The correction for elevation to be applied to the gun for the effect oi rock is of second ary importance. ll desired, however, this can also be determined and applied by using the same rock indicator and comnuinicating the 'me-asure ot-the rock to a second surface cam which may be of the same general design that already described but with the cam constructed to correct for elevation instead of for hearing.

In the earlier parts of this description we have assumed that the deflection for no rock is zero. The follow the rock mechanism should, however, in general not have its axis azimuthally parallel to the line of sight, but should have its axis parallel to the azimuthal direction of the gun itself. Provision may be made for moving the plattorin (or like parts) of the follow the rock mechanism in accordance with the azimuthal direction of the gun, or we may impart to the platform motion in accordance with the azimuthal motion of the gun sight and apply thereto a correction equal to the deflection of the gun, or again we may impart to the platform a motion equal to the algehraical sum of the bearing and deflection in such a way that the azimuthal position of the axis of the rock mechanism is parallel to the azimuthal position of the gun.

An alternative method is to employ a true roll indicator the axis of which is fixed permanently in the fore and aft line of the ship, a true pitch indicator with axis permanently on the beam of the ship, to multiply the angular motion of the roll following mechanism by cos (ad-B), where E is the deflection, to multiply that of the pitch indicator by sin (owl-B), then add the two results algebraically and employ the result in place of that furnished by the single rock indicator azimuthally controlled to follow the azimuthal position of the gun.

We may modify details in several respects, e. g. we may dispense with the surface cam (at all events so far as the effects of rock upon the correction for hearing are concerned) and replace the surface cam by a simple multiplying gear, the value of the correction in bearing being approximately the angle of rock multiplied the tangent of the angleof elevation of the gun for the particular range.

An example oi construction for dealing with the correction in boa 'ing will now be described with reference to the accompanying drawings, in which Figure 1 represents a vertical section, Fig ure 2 a vertical cross section, Figures 3 and at represent sectional elevation and plan respectively of one means of indicating the hearing correction, and Figure 5 is an elevation showing partly in section a multiple cam device which may he used as an alternative device to replace the apparatus shown in Figures 3 and a.

In Figures 1 and 2, 1 is a roll indicator of the Mallock type for indicating the rock supported upon pivots 2 2 and completely immersed'in a suitable liquid 3 contained in a case 4 provided with a corrugated side 5 to allow tor the expansion and contraction of the liquid with changes in temperature). The indicator 1 has a very small amount oigravitational stability, the total weight of 1 being adjusted so that its weight is just about equal to that of the liquid displaced so that the triction at the pivots 2 is extremely small. A. window 6 is provided at the top of the with a mark not shown) on the lower side. The case is moved back and forwards about the axis of the pivots 2 by hand continuously and slowly in con'liorinity with the rock so that this mark is kept opposite a pointer 7 fixed to 1. This operation is effected by handle 10, coupled to a shaft to which is fixed bevel 11 gearing with bevel l2 fixed on shaft 13 to which is lined toothed wheel 14 gearing with 15 to which bevels l5 and 32 are fired. The spindle of jockey wheel 1'? fixed to shaft 18 to which is also fixed bevel l9 gearing with bevel 2O iied to case 1 which is mounted in heari 22 22 concentric with the axis of the pivots 2 2, (Figure 2) supported on a platform 24: mounted on ball bearings so that it canbe rotated in azimuth.

Thus as the ship rocl-cs the OiPStflTtl loching through window 6 moves the handle it) in such a direction and to the requisite amount to keep the case 4 rotated so that pointer '7 (Figure 2) is kept opposite the mark on the window during the rock.

Consideration must now be given to the means for rotation of case 4 azimuthally in conformity with the bearing of the gun so that the axis of case 4 may be kept directed on the target (in the case of no deflection) or kept parallel to the azimuthal direction of the gun itself when deflection arises. In the former case the value of a is communicated to a shaft 26, in the latter the value of a-l-S. Fixed to shaft 26 are two toothed wheels 27 and 28, the former gearing with toothed wheel 29 and the latter with 30. Wheel 29 (loose on shaft 18) is fixed to bevel 31 meshing with jockey 1?. Wheel 30 (loose on shaft 18) is fixed to platform 24 supporting case 4. The gears 27, 29 and 28, 30 are in the ratio of 2 to 1 since the angular motion of the spindle of 17 is half that of bevel-31. Thus, if handle 10 is fixed and shaft 26 is rotated, platform 24 is rotated through a certain angle while the spindle of 17 is rotated through anequal angle so that there is no relative motion of the bevels 19 and 20.

Thus shaft 26 furnishes means for rotating case 4 in azimuth, while handle 10 furnishes means for rotating case 4 about the axis of the pivots 2 2 whatever may he the azimuthal position of 4.

The motion of any of the parts 10, 11, 12, 13, 14, 15, 16 and 32 gives a measure of the rock. To transmit this measure to the multiplying apparatus shown in Figures 3 and 4 the arrangement in Figures 1 and 2 consists of the bevel 32 (fixed to 15 and 16) gearing with a bevel 33 fixed to a coupling 34 (Figure 2). The complementary part of the coupling 34 is shown at (Figure 4) which is fixed to a quick-pitched screw carrying a nut 37. T o prevent the nut from rotating it is provided with a pin 38 engaging in a slot parallel with the screw 36 formed in the framework. Thus as the rock is being followed, nut 37 will be moving backwards and forwards along the axis of screw 36 in conformity with the rock.

The circular measure of the rock has nextto be multiplied by the tangent of the angle of elevation corresponding to the range of the target. For this purpose the range may be communicated to conversion box (not shown, but say after the manner of specification of United States Patent No. 1,339,643, dated 11th May, 1920) whereby range is converted into a magnitude proportional to the tangent of the angle of elevation aforesaid. This value is communicated to a wheel 40 (Figure 4) and thereby to wheels 41 and 42 fixed to screws 43- and 44 respectively. Threaded on these screws are two nuts, one on each screw, of which only one (viz 45 tion that pin is co-ala with fulcrum (i3 h that the The rotation of pinion rod 4?; becomes a measure of the product of the rock and the tangent elevation of the gun correspond ing to the range, for the indi ".tion of rod 49 is proportional to thedisplacement of nut 37 from its zero position (i, e. to tl magnitude of the rock) and is also proportional to the perpendicular distance from fulcrum 53 to the path traced by the centre of pin 50 as the rock varies and this distance has been made proportional to the tangent of the angle of elevation corresponding to the range of the target; thus the rotation of pinion rod 49 becomes a measure of the required correction of hearing.

In place of the means for indicating the correction as shown in Figures 3 and 4, we may alternatively adoptmeans as indicated in Figure Here the value of the rock obtained from shaft 34 (Figure 2) is communicated directly to shaft 60. in this case the gearing between handle it) and bevel 33 (or rather shaft must be altered in such a way that the total rotation of 60 from maximum rock on one side to maxin'uun rock on the other shall be less than one revolution. Thus as the ship rocks a cam surf re 61 fixed to shaft 60 oscillates in conformity with the rock. The value of the range is communicated (say according to a uniform scale) to the apparatus by the rotation of screw 62 upon which there is threaded a nut 63 (suitably guided) carrying groove in which slides a rack 64 with sloping teeth gearing with a long spiral pinion 65 whose rotation furnishes a measure of the requisite correction of bearing. Suitable forces either elastic or gravitational keep the roller at the lower end of G4 in contact with the cam surface 61. In this case as the range alters, i. e. as 63 is moved from left to right, the spiral pinion 65 rotates even although the rack 64 does not slide relatively to the nut 63. Thus the spiral pinion 65 is arranged to do the rough motion required while the corrections only are dealt with by the cam surface 61. It will be recognized that in mechanism of this character relative axial motion may be obtained by moving either the cam surface, the plunger or both, and that instead of applying indications according to rock to 60 it may be imparted to 62 and indications of range or gun elevation instead of being in'ipartcd to 62 may he imparted to 60.

While the apparatus illustrated in Figures 3 and 4: is only applicable for the multiplication of two quantities-411 the case referred to 1) reel: and tangent of elevation of gun-the apparatus illustrated in Figure 5 is capable of giving the resultant value of any function of the two independent variables (1) rock and range. It is therefore capable of being utilized for indicatin not only the correction for bearing but also (if cam surface 61 is suitably formed) the correction for range or the correction for the elevation of the gun.

Vi e claim 1. Apparatus comprising means for indieating rock, calculating mechanism, means for transmitting to the calculating mechanism motion in accordance with indications f rock and means for transmitting to the calculating mechanism at any point of the rock motion in accordance with a function of the range or angle of elevation of the gun, for the purposes set forth.

2. Apparatus comprising a roll indicator for indicating rock, calculating mechanism, means for transmitting to the calculating mechanism motion in accordance with indications obtained from the rock indicator and means for transmitting to the calculating mechanism at any point of the rock motion in accordance with a function of the range or angle of elevation of the gun, for the purposes set forth.

Apparatus comprising a roll indicator for indicating rock mounted capable of azimuthal rotation, calculating mechanism, means for transmitting to the calculating mechanism motion in accordance with indications obtained from the rock indicator and means for transmitting to the calculating mechanism at any point of the rock motion in accordance with a function of the range or angle of elevation of the gun, for the purposes set forth.

4. Apparatus comprising means for indicating rock, calculating mechanism, toothed gear mechanism for transmitting to the calculating mechanism motion in accordance ance with a function of the range or angleof elevation of the gun, for the purposes set forth.

6. apparatus comprising means for indieating rock in combination with calculating mechanism consisting of a cam surface, a plunger bearing upon the cam surface and having a rack, means for producing relati-ve axial translation of the plunger and cam surface, and a long pinion in gear with the rack of the plunger, for the purposes set forth.

7. Apparatus comprising means for indicating rock, in combination with calculating mechanism consisting of a cam surface rotatable in accordance with magnitude of rock, a plunger bearing upon the cam surface and having a rack, means for translat ing the plunger parallel to the axis of the cam surface in accordance with range or angle of elevation of the gun and a long pinion in gear with the rack the amount of rotation of which pinion furnishing a measure of the correction required.

8. Apparatus comprising means for indicating rock, in combination with calculating mechanism consisting of a cam surface rotatable in accordance with magnitude of rock, a plunger bearing upon the cam surface and having a rack, means for translating the plunger parallel to the axis of the cam surface in accordance with range or angle of elevation of the gun and a long spiral pinion in gear with the rack the amount ofirotation of which pinion furnishing a measure of the correction required.

ARCHIBALD BARR. WILLIAM STROUD. 

